2013: Year of the Cicada

As temperatures rise in the American north-east, the ground is thawing and the cicadas are waiting to emerge. This region of the world is home to Periodical Cicadas of the genus Magicicada. There are seven recognized species in this genus, four have a 13-year life-cycle and three have a 17 year life-cycle. It has been17 years since the last emergence, so in a few weeks the nymphs will emerge and begin their highly anticipated arrival.

Brood II is generally found along the eastern coast of the US.

Why 17 years? The honest answer is nobody knows for sure. Scientists speculate the juveniles can monitor the temperature changes throughout the years, count out 17 and then emerge. Emerging all at once increases their chance as a species to survive, as there is little chance the billions of them could be wiped out at once. There are fourteen different broods which have their own territories that overlap. Brood II began in 1979, returned in 1996, and their children will have their turn this spring of 2013.

Cicadas spend most of their life underground as immature nymphs sucking sap from tree roots until the last month when they emerge as adults. Most cicadas follow this same life-cycle (annual cicadas), but what makes periodic cicadas unique is that all the developing nymphs emerge all in synchrony. When the soil temperature at a depth of 20 cm raises above 17 degrees Celsius, the nymphs will crawl backwards out of the soil and start to climb the nearest tree for the last molt of their life.

This massive emergence is an absolute terror to an entomophobe, but to an entomologist this event is akin to an astronomer's view of a rare comet or solar eclipse. These swarms can reach impressive densities, as many as 1.4 million per acre! but tens to hundreds of thousands are more common. With such incredible numbers of these insects mucking about, you'd expect them to be quite damaging, but they're not. They don't sting or bite (unless you're mistaken for a tree branch) they only cause a slight to severe annoyance which can be remedied by purchasing some good ear-plugs. Many forward thinking residents will plan their spring vacations around these weeks, after sealing the windows and doors of their home.

   

Nathan Mundhenk
Two hour molt of nymph into adult cicada

The few short weeks the cicadas live as adults are spent trying to find a mate. They do this by performing an orchestra of clicks, chirps and hisses that fade into a deafening wall of white noise. This chorus can reach 90 decibels, about the same volume of a jack-hammer. This background static heard throughout the north-east can be dissected into nine different sounds made by the three different species. The three species which follow the 17-year cycle are Magicicada septendecim, septencassini, and septendecula, each with their own unique mating call. Cassini is responsible for the white-noise hiss, Septendecula creates an irregular, rhythmic buzz, and Septendecim make a "Pharaoh" type sound, a long suspended note which drops to a lower note at the end. A female cicada listens to the music and can detect males which are close and she responds with a wing-click exactly one-third of a second after the male finishes his sound. This then initiates a type of "Marco-Polo" game. The male makes a new type of call, a part two of their love-duet as they move closer together. The male repeats a faster version of his call and the female responds with another wing-click. At this pint the male and female have found each other and after one more even quicker call-and-response the two cicadas can do what they've been preparing their whole life for. The females will lay their eggs in branches and when they hatch the larvae will fall onto the earth, burrow down and find a tree root to attach themselves to and wait another 17 years.




Sources:
www.magicicada.org

The Telegraph: Swarmageddon

http://www.radiolab.org

Mass Production of Beneficial Insects

Everyone knows about the constant battle being fought between farmers and the pests on their crops. So far the farmer's only real defense has been to douse their fields with harmful pesticides in hopes to exterminate all the little buggers. But this strategy has always had unintended consequences; non-target organisms can be harmed, chemicals can leach and contaminate ground water, and inevitably the pests will develop a resistance to the toxin over time. 

We try to plant our gardens and farms in a way which will invite beneficial insects on to our land to do the dirty work for us.There is great and every growing knowledge on different biological control options. But the aphid to parasitic wasp ratio always seems a little skewed in the aphids favour. If only we could just sprinkle some of those predatory insects onto our crops, like some sort of vegetable saving pixie-dust.

A company in Israel called Bio-Bee Biological Systems is working on just that. They focus on mass production of beneficial insects and mites for agricultural operations locally and internationally. In large greenhouses they create ideal habitats to breed insects such as bumble bees, parasitic wasps, minute pirate bugs and other arthropods such as the predatory mite. In an effort to reduce fruit fly populations Bio-Bee also produces a line of  sterile male Mediterranean Fruit Flies which are released in fruit orchards.

Releasing one gram of predatory mites (80,000 in one small vial) is enough to protect an acre for the season. In just one day a predatory mite can eat up to 5 spider mites or 15-20 of their eggs.

 Farms that have adopted this use of  pre-packaged insects have seen a 75-80% reduction in their pesticide application - a huge savings. Large farms can spend up to $2.5 billion on insecticides,but to  convert to a biological approach, control will cost around 250 million.  Workers are thrilled to not have to put on the bio-hazard suits and risk their own health and safety when handling applying pesticides. Consumers are equally thrilled to purchase produce with a less substantial carbon footprint. And the best part - it is extremely rare for a pest to develop immunity or resistance to the predatory insect.

It seems like such  an obvious solution, I don't know why it's not more common!

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